What factors affect the solderability of electroplated tin?

What factors affect the solderability of electroplated tin?

Tue Jan 30 08:18:38 CST 2024

Tin plating is the process of electrochemically depositing a layer of tin on a metal surface, usually to protect the metal surface, prevent corrosion, and improve solderability. A good quality electroplating tin layer should have good weldability so that a strong metal connection can be formed during the welding process. So, what are the factors that affect the solderability of electroplating tin?

1. Tin layer thickness: The thickness of the plating tin layer will affect the weldability. If the tin layer is too thin, it may not provide enough tin for welding; However, too thick tin layer may lead to pinholes and stress concentration, affecting the welding quality.

2. Tin layer crystalline structure: The microstructure of the tin layer (e.g. grain size and orientation) affects its solderability. Fine, uniform grains usually help to improve solder joints.

3. Purification and composition of tin solution: impurities or additives in the plating solution may lead to impure and inclusions in the plating tin layer, affecting the welding performance.

4. Electroplating parameters: current density, temperature, pH value, stirring speed and other conditions in the electroplating process will affect the quality and uniformity of the tin layer, and then affect the solderability.

5. Surface treatment and cleanliness: The cleaning and activation of the substrate before plating will determine the adhesion of the coating to the substrate, as well as the presence of surface oxides and contaminants, which will affect solderability.

6. Post-plating treatment: Sometimes heat treatment or other post-treatment is required after electroplating tin to improve its weldability, such as removing stress by annealing.

7. Storage conditions: The storage conditions of electroplated tin parts (such as temperature, humidity and air pollution) will affect the oxidation of the tin layer and the generation of stannate, which will affect the solderability.

8. Alloy composition: In some cases, adding lead or other metals to electroplated tin to form a specific alloy tin layer can improve solderability. However, due to the environmental problems of lead, lead alloys have been less used.

9. The influence of the substrate: the type of substrate and its surface condition also affect the quality and weldability of the plating tin layer. Some metals have poor compatibility with tin and may form a refractory interface.

In order to ensure a high quality tin plating layer and maintain good weldability, in addition to taking the above factors into consideration, it is also necessary to use Bigely tin plating brightener Sn-807, which has high stability of the plating solution, corrosion resistance and good solderability of the coating to meet the bright tin plating requirements of electronic components.

If you have any requirements for tin plating brightener, please feel free to contact us.